TW201420667A - Resist underlayer film forming composition containing novolak resin having polynuclear phenols - Google Patents

Abstract

To provide a composition for forming a resist underlayer film, which can be used for the formation of a resist underlayer film that has high dry etching resistance and high wiggling resistance and that can exert good flatting performance and good filling performance in an uneven part or a depressed part. A composition for forming a resist underlayer film, which contains a phenol-novolac resin produced by reacting a compound with an aromatic aldehyde or an aromatic ketone in the presence of an acidic catalyst, wherein the compound has at least three phenol groups and each of the phenol groups has such a structure that each of the phenol groups is bound to a tertiary carbon atom or such a structure that each of the phenol groups is bound to a quaternary carbon atom having a methyl group bound thereto. The phenol-novolac resin comprises a unit structure represented by formula (1), a unit structure represented by formula (2), a unit structure represented by formula (3), a unit structure represented by formula (4) or a combination of any two or more of the aforementioned unit structures.

Description

Resistant underlayer film forming composition containing polynuclear phenolic novolac resin

The present invention relates to a resist formation underlayer film forming composition effective for processing a semiconductor substrate, a resist pattern forming method using the resist underlayer film forming composition, and a method of manufacturing a semiconductor device.

In the manufacture of semiconductor devices, microfabrication is performed by lithography using a photoresist composition. In the microfabrication, a thin film of a photoresist composition is formed on a substrate to be processed such as a tantalum wafer, and a pattern of a pattern in which a semiconductor device is drawn is placed thereon to irradiate active light such as ultraviolet rays. For example, the obtained photoresist pattern is used as a protective film, and a substrate to be processed such as a germanium wafer is etched. However, in recent years, semiconductor devices have progressed toward high integration, and the active light used has also been shortened from KrF excimer laser (248 nm) to ArF excimer laser (193 nm). Along with this, the influence of the diffused or irradiated active light from the substrate becomes a big problem, and an anti-protection is provided between the photoresist and the substrate to be processed. The method of Bottom Anti-Reflective Coating (BARC) is widely reviewed.

Further, as the resist pattern is made finer, the problem of resolution or the problem of collapse of the resist pattern formed after development occurs, and in order to solve this solution, it is desirable to form a thin film of the resist. However, due to the thinning of the resist, it is difficult to obtain a sufficient resist pattern thickness in the substrate processing, so that the resist layer is formed not only in the resist pattern but also between the resist and the processed semiconductor substrate. The film also needs to be maintained as a process for masking during substrate processing. For the purpose of thin film formation of such a resist film thickness, it is known to form at least two layers of a resist underlayer film, and the resist underlayer film is used as a lithography process for etching a mask. Here, as the resist underlayer film for the lithography process, it is necessary to have high etching resistance to the etching gas (for example, fluorocarbon) in the dry etching step.

Further, as the resist pattern is miniaturized, in the underlayer film which becomes the resist mask, an irregular pattern of a resist underlayer film called wigling occurs at the time of the dry etching step. Bending, the possibility of hindering the formation of a desired pattern occurs during processing of the semiconductor substrate. Therefore, in the underlayer film which is the resist of the etching mask, it is required to suppress the underlying film material having high sloshing resistance even in the case of the fine pattern. Further, in the resist underlayer film, a resist underlayer film forming composition which can sufficiently cover the step formed on the surface of the semiconductor substrate or the flattening or embedding property of the uneven portion is required.

As the polymer for the above-mentioned resist underlayer film, for example, the following can be exemplified.

A composition film of a lower layer film using a polyethylene carbazole is exemplified (see Patent Document 1, Patent Document 2, and Patent Document 3).

There is disclosed a resist underlayer film forming composition using a phenol phenol novolak resin (for example, refer to Patent Document 4).

There is a composition for forming a lower layer film of a resist using a naphthol novolak novolak resin (for example, see Patent Document 5).

There is a resist underlayer film forming composition which discloses a resin containing an anthracene phenol and an arylalkylene group as a repeating unit (see, for example, Patent Document 6 and Patent Document 7).

There is disclosed a composition for forming an underlayer film using a oxazole novolac varnish (for example, see Patent Document 8).

There is disclosed a composition for forming an underlayer film using a polynuclear phenol novolak (see, for example, Patent Document 9).

Prior technical literature Patent literature

Patent Document 1: Special Opening No. 2-293850

Patent Document 2: JP-A-1-15050

Patent Document 3: Special Kaiping No. 2-22657

Patent Document 4: Special Opening 2005-128509

Patent Document 5: Special Opening 2007-199653

Patent Document 6: Special Opening 2007-178974

Patent Document 7: U.S. Invention Patent No. 7378217

Patent Document 8: International Open Booklet WO2010/147155

Patent Document 9: Special Opening 2006-259249

The present invention provides a resist underlayer film forming composition for a lithography process for semiconductor device fabrication. Further, the present invention has high dry etching resistance to an etching gas such as fluorocarbon, and suppresses sway of the underlayer film of the resist in the dry etching step, thereby achieving miniaturization of semiconductor substrate processing. Furthermore, in order to exhibit good planarization or embedding property for the surface of the semiconductor substrate having the step or the uneven portion, the present invention provides a coating agent having a high solubility in a resist solvent and a spin coating method. The underlayer film forms a composition.

The first aspect of the invention is a resist underlayer film forming composition comprising a structure having at least three phenol groups bonded to a third-order carbon atom, or having the phenol group bonded thereto a phenol novolak resin obtained by reacting a compound having a fourth-order carbon atom bonded to a methyl group with an aromatic aldehyde or an aromatic ketone in the presence of an acidic catalyst;

The second aspect is the resist underlayer film forming composition according to the first aspect, wherein the phenol novolak resin comprises a unit structure of the following formula (1), a unit structure of the formula (2), a unit structure of the formula (3), Unit structure of formula (4) or a combination of their unit structures: In the formula (1), the formula (2), the formula (3), and the formula (4), the A group has an organic group having at least three phenol groups and the phenol group is bonded to the third-order carbon atom, and B ¹ , B ² , B ³ and B ⁴ each represent the formula (5): (In the formula (5), C ¹ represents an aryl or heterocyclic group having 6 to 40 carbon atoms which may be substituted by a halogen group, a nitro group, an amine group or a hydroxyl group, and C ² represents a hydrogen atom or may be a halogen group or a nitro group. , an amino group or a hydroxy group substituted with an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms or a heterocyclic group, and C ¹ and C ² may also form a ring together with the carbon atom to which they are bonded) The third aspect is the resist underlayer film forming composition according to the second aspect, wherein the A system is represented by the formula (6). (In the formula (6), T-based single bond, an alkylene group having a carbon number of 1 to 10, carbon atoms or an arylene group having 6 to 40, X ¹ and X ² are each a hydrogen atom or a methyl-based, R ¹ to R ^{4 is} each a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and each of R ⁵ to R ⁸ is an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms, and each of n1 to n4 represents an integer of 0 to 3 Each of the phenolic groups is appropriately bonded to the above B ¹ , B ² , B ³ and B ⁴ ; and the fourth aspect is the resist underlayer film forming composition according to the second aspect, wherein the above A is a formula (7) ) said that (In the formula (7), each of R ⁹ to R ¹¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and each of R ¹² to R ^{14 has} an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms; X ³ is a hydrogen atom or a methyl group, and n5 to n7 each represent an integer of 0 to 3, and each phenol group is appropriately bonded to the above B ¹ , B ² , B ³ and B ⁴ ); The resist underlayer film forming composition according to any one of the first aspect to the fourth aspect, wherein the C ¹ -based fluorenyl group or a fluorenyl group; and the sixth aspect is the lower layer of the resist according to any one of the first aspect to the fourth aspect; The film forming composition further contains a crosslinking agent, and the method of forming a lower layer film forming composition according to any one of the first aspect to the fifth aspect, further comprising an acid and/or an acid generating agent; The eighth aspect is a resist underlayer film obtained by applying a resist underlayer film forming composition according to any one of the first aspect to the seventh aspect to a semiconductor substrate, and baking the film; A method for forming a resist pattern for use in the manufacture of a semiconductor, comprising coating a resist underlayer film forming composition according to any one of the first to seventh aspects A method of forming a lower layer film by firing on a semiconductor substrate, and a method of manufacturing a semiconductor device according to the tenth aspect, comprising: blocking the semiconductor substrate from any one of the first to seventh aspects a step of forming a composition to form an underlayer film, a step of forming a resist film thereon, a step of forming a resist pattern by irradiation and development of light or electron lines, and etching according to a resist pattern a step of processing the underlayer film and a step of processing the semiconductor substrate by the patterned underlayer film; the eleventh aspect is a method for fabricating a semiconductor device, comprising: on the semiconductor substrate, by the first viewpoint to The step of forming a lower layer film by forming a composition of the underlayer film as described in any of the above points, forming a hard mask thereon, and further forming a resist film thereon by irradiation with light or electron rays a step of forming a resist pattern with development, a step of etching a hard mask by a resist pattern, a step of etching the underlayer film by a patterned hard mask, and a pattern by patterning Lower film to process Step conductor of the substrate; and a second 12 point of view of manufacturing method according to the eleventh aspect, wherein the hard mask by vapor deposition system of the inorganic actors.

By forming the composition of the resist underlayer film of the present invention, it is possible to provide an excellent underlayer film having high dry etching resistance to an etching gas such as a fluorocarbon.

In order to prevent the resist pattern from collapsing after development as the resist pattern is miniaturized, thinning of the resist is performed. In such a thin film resist, the resist pattern is transferred to the underlying film by an etching process, the underlying film is used as a mask for the substrate processing process, or the resist pattern is repeatedly transferred by an etching process to the resist pattern. The lower layer film is further transferred to the lower layer film by using a different etching gas to transfer the pattern transferred to the underlying film, and finally the substrate processing process is performed. The resist underlayer film of the present invention and the forming composition thereof are effective for the process, and when the substrate is processed by using the resist underlayer film of the present invention, the substrate is processed (for example, a thermal yttrium oxide film, a yttrium oxide film, a polycrystalline ruthenium film on the substrate) Etc.) has sufficient etch resistance.

Further, the resist underlayer film of the present invention can be used as a planarization film, a resist underlayer film, a resist layer of a resist layer, and a film having dry etching selectivity. Thereby, the formation of the resist pattern in the lithography process of semiconductor fabrication can be easily and accurately performed. In particular, the occurrence of sway of the resist underlayer film (bending of an irregular pattern) in the dry etching step can be suppressed. Further, the surface of the semiconductor substrate having the step or the uneven portion can be coated without irregularities or holes, and the flatness or embedding property can be excellent.

Forming a resist underlayer film formed on the substrate by the resist underlayer film forming composition of the present invention, forming a hard mask thereon, forming a resist film thereon, and forming a resist pattern by exposure and development, The resist pattern is transferred to the hard mask, and the resist pattern transferred to the hard mask is transferred to the resist underlayer film, and the resist underlayer film is used to process the semiconductor substrate. In the process, when the hard mask is carried out by a coating type composition containing an organic polymer or an inorganic polymer and a solvent, it may be carried out by vacuum evaporation of an inorganic substance. In vacuum evaporation of an inorganic substance such as bismuth oxynitride, an evaporation material is deposited on the surface of the underlayer film of the resist, and the temperature of the surface of the lower film of the resist rises to about 400 °C. The polymer used in the present invention is a novolak resin composed of a combination of the formula (1), the formula (2), the formula (3), the formula (4) or the like, and has high heat resistance even if it is evaporated. The deposition of matter does not cause thermal degradation. Further, the present underlayer film forming composition has high solubility in a resist solvent and is a coating type composition excellent in spin coating property.

Fig. 1 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Example 1.

Fig. 2 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Example 3.

Fig. 3 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Example 4.

Fig. 4 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Example 6.

Fig. 5 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Example 7.

Fig. 6 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Example 8.

Fig. 7 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Example 9.

Fig. 8 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Example 10.

Fig. 9 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Example 11.

Fig. 10 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Comparative Example 1.

Fig. 11 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the flattening test of Comparative Example 2.

Fig. 12 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Example 1.

Fig. 13 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Example 3.

Fig. 14 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Example 4.

Fig. 15 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Example 6.

Fig. 16 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Example 7.

Fig. 17 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Example 8.

Fig. 18 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Example 9.

Fig. 19 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Example 10.

Fig. 20 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Example 11.

Fig. 21 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Comparative Example 1.

Fig. 22 is a cross-sectional SEM photograph (magnification: 100,000 times) showing the results of the embedding test of Comparative Example 2.

Form of implementing the invention

The present invention is a resist underlayer film forming composition containing a structure having at least three phenol groups bonded to a third-order carbon atom, or having a phenol group bonded to a methyl group. A phenol novolak resin obtained by reacting a compound having a structure of a fourth-order carbon atom with an aromatic aldehyde or an aromatic ketone in the presence of an acid catalyst.

In the present invention, the above-mentioned lithographic underlayer film forming composition contains the above resin and a solvent. Further, a crosslinking agent, an acid, an acid generator, a surfactant, or the like may be contained as needed. The solid content of this composition is 0.1 to 70% by mass or 0.1 to 60% by mass. Solid component self-resistive agent underlayer film formation The content ratio of all components after removing the solvent in the composition. The above polymer may be contained in a solid content of 1 to 100% by mass, or 1 to 99.9% by mass, or 50 to 99.9% by mass, or 50 to 95% by mass, or 50 to 90% by mass.

The polymer used in the present invention has a weight average molecular weight of 600 to 1,000,000 or 600 to 200,000.

The phenol novolak resin contains a unit structure of the following formula (1), a unit structure of the formula (2), a unit structure of the formula (3), a unit structure of the formula (4), or a combination of the unit structures.

In the formula (1), the formula (2), the formula (3), and the formula (4), the structure A has a structure having at least three phenol groups and the phenol group is bonded to the third-order carbon atom, or has the phenol group. The organic group bonded to the structure of the fourth-order carbon atom to which the methyl group is bonded, and B ¹ , B ² , B ³ and B ⁴ each represent the formula (5).

In the formula (5), C ¹ represents an aryl or heterocyclic group having 6 to 40 carbon atoms which may be substituted by a halogen group, a nitro group, an amine group or a hydroxyl group, and C ² represents a hydrogen atom or may be a halogen group or a nitro group. The amino group or the hydroxy group is substituted with an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms or a heterocyclic group, and C ¹ and C ² may form a ring together with the carbon atom to which they are bonded.

Examples of the alkyl group having 1 to 10 carbon atoms in the alkyl group include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a cyclopropyl group, an n-butyl group, an isobutyl group, a second butyl group, and a third group. Butyl, cyclobutyl, 1-methyl-cyclopropyl, 2-methyl-cyclopropyl, n-pentyl, 1-methyl-n-butyl, 2-methyl-n-butyl, 3-methyl Base-n-butyl, 1,1-dimethyl-n-propyl, 1,2-dimethyl-n-propyl, 2,2-dimethyl-n-propyl, 1-ethyl-n-propyl , cyclopentyl, 1-methyl-cyclobutyl, 2- Methyl-cyclobutyl, 3-methyl-cyclobutyl, 1,2-dimethyl-cyclopropyl, 2,3-dimethyl-cyclopropyl, 1-ethyl-cyclopropyl, 2 -ethyl-cyclopropyl, n-hexyl, 1-methyl-n-pentyl, 2-methyl-n-pentyl, 3-methyl-n-pentyl, 4-methyl-n-pentyl, 1,1 - dimethyl-n-butyl, 1,2-dimethyl-n-butyl, 1,3-dimethyl-n-butyl, 2,2-dimethyl-n-butyl, 2,3-di Methyl-n-butyl, 3,3-dimethyl-n-butyl, 1-ethyl-n-butyl, 2-ethyl-n-butyl, 1,1,2-trimethyl-n-propyl 1,2,2-trimethyl-n-propyl, 1-ethyl-1-methyl-n-propyl, 1-ethyl-2-methyl-n-propyl, cyclohexyl, 1-methyl -cyclopentyl, 2-methyl-cyclopentyl, 3-methyl-cyclopentyl, 1-ethyl-cyclobutyl, 2-ethyl-cyclobutyl, 3-ethyl-cyclobutyl, 1,2-dimethyl-cyclobutyl, 1,3-dimethyl-cyclobutyl, 2,2-dimethyl-cyclobutyl, 2,3-dimethyl-cyclobutyl, 2, 4-Dimethyl-cyclobutyl, 3,3-dimethyl-cyclobutyl, 1-n-propyl-cyclopropyl, 2-n-propyl-cyclopropyl, 1-isopropyl-cyclopropane Base, 2-isopropyl-cyclopropyl, 1,2,2-trimethyl-cyclopropyl, 1,2,3-trimethyl-cyclopropyl, 2,2,3-tri -cyclopropyl, 1-ethyl-2-methyl-cyclopropyl, 2-ethyl-1-methyl-cyclopropyl, 2-ethyl-2-methyl-cyclopropyl and 2- Ethyl-3-methyl-cyclopropyl and the like.

Examples of the aryl group having 6 to 40 carbon atoms of the aryl group include a phenyl group, an o-methylphenyl group, a m-methylphenyl group, a p-methylphenyl group, an o-chlorophenyl group, a m-chlorophenyl group, and a p-chloro group. Phenyl, o-fluorophenyl, p-fluorophenyl, o-methoxyphenyl, p-methoxyphenyl, p-nitrophenyl, p-cyanophenyl, α-naphthyl, β-naphthyl, ortho Biphenyl, m-phenyl, p-biphenyl, 1-indenyl, 2-indenyl, 9-fluorenyl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl and 9- Fiji.

The heterocyclic group is preferably an organic group composed of a heterocyclic ring containing a 5- to 6-membered ring of a nitrogen, sulfur or oxygen atom, and examples thereof include a pyrrolyl group, a furyl group, a thienyl group, and an imidazolyl group. Azyl, thiazolyl, pyrazolyl, iso Azyl, isothiazolyl, pyridyl, tri Base, three Triketone group and the like.

In the unit structure of the above formula (1), the unit structure of the formula (2), the unit structure of the formula (3), the unit structure of the formula (4), or a combination thereof, A may be represented by the formula (6). . In the formula (6), a T-based single bond, an alkylene group having 1 to 10 carbon atoms, or an extended aryl group having 6 to 40 carbon atoms, each of X ¹ and X ² is a hydrogen atom or a methyl group, and R ¹ to R ^{4 are each.} Each is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁵ to R ⁸ are each an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms, and each of n1 to n4 represents an integer of 0 to 3, Each phenol group is suitably bonded to the above B ¹ , B ² , B ³ and B ⁴ .

Examples of the alkyl group and the aryl group include the above groups. Further, examples of the alkylene group include an alkylene group derived from the above alkyl group. Further, examples of the aryl group include an extended aryl group derived from the above aryl group.

In the unit structure of the above formula (1), the unit structure of the formula (2), the unit structure of the formula (3), the unit structure of the formula (4), or a combination of the unit structures, A may be represented by the formula (7). . In the formula (7), each of R ⁹ to R ¹¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and each of R ¹² to R ^{14 has} an alkyl group of 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms. X ³ is a hydrogen atom or a methyl group, and n5 to n7 each represent an integer of 0 to 3, and each phenol group is appropriately bonded to the above B ¹ , B ² , B ³ and B ⁴ . Here, examples of the alkyl group and the aryl group include the above examples.

The above-mentioned A-based polynuclear phenol used in the present invention is a compound having at least three or more phenyl groups in one molecule, and the phenyl group has at least one The above hydroxyl group or alkoxy group.

The novolac resin used in the present invention is a novolak resin obtained by condensing a polynuclear phenol with an aldehyde or a ketone, and the polynuclear phenol may be used singly or in combination of two or more kinds.

Examples of the polynuclear phenol produced by using the polymer of the present invention include 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane and 1,1,2,2-tetra (3-methyl). 4-hydroxyphenyl)ethane, 1,1,2,2-tetrakis(4-hydroxymethylphenyl)ethane, 1,1,3,3-tetrakis(4-hydroxyphenyl)propane, α,α,α',α'-tetrakis(4-hydroxyphenyl)-p-xylene, α,α,α',α'-tetrakis(3-methyl-4-hydroxyphenyl)-p-xylene , α,α,α',α'-tetrakis(4-methoxyphenyl)-p-xylene, α,α,α',α'-tetrakis(4-hydroxyphenyl)-2,5-di Methyl-p-xylene, α,α,α',α'-tetrakis(4-hydroxyphenylmethyl)-naphthalene, tris(4-hydroxyphenyl)methane, tris(4-hydroxyphenyl)ethane Wait.

Examples of the aldehyde used in the production of the polymer of the present invention include formaldehyde, trioxane, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, valeraldehyde, caproic aldehyde, and 2-methyl group. Butyl aldehyde, hexyl aldehyde, undecal aldehyde, 7-methoxy-3,7-dimethyl octanal, cyclohexanal, 3-methyl-2-butyl aldehyde, glyoxal, Saturated aliphatic aldehydes such as malondialdehyde, succinaldehyde, glutaraldehyde, glutaraldehyde, and adipaldehyde; unsaturated aliphatic aldehydes such as acrolein and methacrolein, and furfural, pyridaldehyde, etc. Cyclic aldehydes, benzaldehyde, naphthaldehyde, 9-furfural, phenanthrene, salicylaldehyde, phenylacetaldehyde, 3-phenylpropanal, tolualdehyde, (N,N-dimethylamino)benzene An aromatic aldehyde such as formaldehyde, ethoxylated benzaldehyde or 1-indolylaldehyde. Particularly preferred is an aromatic aldehyde, and more preferably 9-nonanal or 1-nonanaldehyde.

Further, a ketone-based diaryl ketone used in the production of the polymer of the present invention Examples thereof include diphenyl ketone, phenyl naphthyl ketone, dinaphthyl ketone, phenyl tolyl ketone, xylyl ketone, and 9-fluorenone.

The polymer used in the present invention is a novolak resin obtained by condensing polynuclear phenols with aldehydes or ketones. In the condensation reaction, an aldehyde or a ketone may be used in an amount of 0.1 to 10 equivalents, preferably 0.1 to 2 equivalents, per equivalent of the phenyl group involved in the reaction contained in the polynuclear phenol.

Examples of the acid catalyst used in the condensation reaction include mineral acids such as sulfuric acid, phosphoric acid, and perchloric acid, organic sulfonic acids such as p-toluenesulfonic acid, p-toluenesulfonic acid monohydrate, and methanesulfonic acid, and formic acid and oxalic acid. And other carboxylic acids. The amount of the acid catalyst used varies depending on the type of the acid to be used. In general, it is 0.001 to 10,000 parts by mass, preferably 0.01 to 1000 parts by mass, more preferably 0.1 to 100 parts by mass, based on 100 parts by mass of the total of the carbazole or the carbazole and the hydroxyl group-containing aromatic compound.

The above condensation reaction can be carried out without a solvent, but it is usually carried out using a solvent. As the solvent, any solvent can be used as long as it does not interfere with the reaction. For example, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, tetrahydrofuran, and two An ether such as an alkane. Further, the acid catalyst to be used may be a solvent as long as it is, for example, a liquid such as formic acid.

The reaction temperature at the time of condensation is usually from 40 ° C to 200 ° C. The reaction time varies depending on the reaction temperature, but it is usually from about 30 minutes to about 50 hours.

The weight average molecular weight Mw of the polymer obtained as above is usually from 500 to 1,000,000 or from 600 to 200,000.

The phenol novolak resin used in the present invention may, for example, be exemplified below.

The resist underlayer film forming composition of the present invention may contain a crosslinking agent component. Examples of the crosslinking agent include melamine-based, substituted urea-based, and the like. Preferred are crosslinkers having at least 2 crosslinks to form substituents, which are methoxymethylated glycoluril, butoxymethylated glycoluril, methoxymethylated melamine, butoxymethylated Melamine, methoxymethylated benzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea, butoxymethylated urea, methoxymethylated thiourea, or A compound such as methoxymethylated thiourea. Further, a condensate of these compounds can also be used.

Further, as the crosslinking agent, a crosslinking agent having high heat resistance can be used. As the crosslinking agent having high heat resistance, a compound containing a crosslinking group to form a substituent having an aromatic ring (for example, a benzene ring or a naphthalene ring) in the molecule is preferably used.

The compound may be a compound having a partial structure of the following formula (9) or a polymer or oligomer having a repeating unit of the following formula (10).

R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and examples of the alkyl group described above can be used. Further, n15 is an integer of 1 to 4, n16 is an integer of 1 to (5-n15), and (n15+n16) represents an integer of 2 to 5. N17 is an integer of 1 to 4, n18 is 0 to (4-n17), and (n17+n18) represents an integer of 1 to 4. The number of oligomer and polymer repeat unit configurations can range from 2 to 100, or from 2 to 50.

The compounds, polymers and oligomers of the formulae (9) and (10) are exemplified below.

The above compounds are obtained from products of Asahi Organic Materials Co., Ltd. and Honshu Chemical Industry Co., Ltd. For example, among the above crosslinking agents, the compound of the formula (11-24) can be obtained from Asahi Organic Materials Co., Ltd., trade name TM-BIP-A.

The amount of the crosslinking agent to be added varies depending on the coating solvent to be used, the base substrate to be used, the desired solution viscosity, the desired film shape, and the like, but is 0.001 to 80% by mass based on the total solid content. % is preferably from 0.01 to 50% by mass, more preferably from 0.05 to 40% by mass. Such payment The crosslinking agent may also undergo a crosslinking reaction by condensation of itself, but in the above polymer of the present invention, when a crosslinking substituent is present, a crosslinking reaction with the crosslinking substituent may occur.

In the present invention, as a catalyst for promoting the above crosslinking reaction, p-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridinium p-toluenesulfonic acid, salicylic acid, 5-sulfosalicylic acid, 4 may be blended. - acidic compounds such as phenolsulfonic acid, camphorsulfonic acid, 4-chlorobenzenesulfonic acid, benzenedisulfonic acid, 1-naphthalenesulfonic acid, citric acid, benzoic acid, hydroxybenzoic acid, naphthalenecarboxylic acid, etc. and/or 2,4 , 4,6-tetrabromocyclohexadienone, benzoin tosylate, 2-nitrobenzyl tosylate, other organic sulfonic acid alkyl esters and the like. The blending amount is 0.0001 to 20% by mass, preferably 0.0005 to 10% by mass, and more preferably 0.01 to 3% by mass based on the total solid content.

In the lithographic resistive underlayer film of the present invention, a composition is formed, and a photoacid generator may be added in order to match the acidity of the photoresist coated on the upper layer in the lithography step. Preferred examples of the photoacid generator include bismuth salt-based photoacids such as bis(4-t-butylphenyl)iodonium trifluoromethanesulfonate and triphenylsulfonium trifluoromethanesulfonate. Producer, phenyl-bis(trichloromethyl)-s-three The halogen-containing compound is a photoacid generator, a benzoin tosylate, a sulfonic acid photoacid generator such as N-hydroxysuccinimide trifluoromethanesulfonate, or the like. The photoacid generator is from 0.2 to 10% by mass, preferably from 0.4 to 5% by mass, based on the total solid content.

In addition to the above, a light absorbing agent, a rheology modifier, an adhesion aid, a surfactant, and the like may be further added to the underlayer film material for lithography of the present invention.

As a further added light absorbing agent, for example, it is preferable to use a commercially available light absorbing agent described in "Technology and Market for Industrial Pigment" (CMC Publishing) or "Dye Handbook" (edited by the Society of Organic Synthetic Chemistry), for example, CI disperse yellow is preferably used. 1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82, 88, 90, 93, 102, 114 and 124; CI disperse orange 1, 5, 13, 25, 29, 30, 31, 44, 57, 72 and 73; CI disperse red 1, 5, 7, 13, 17, 19, 43, 50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199 and 210; CI Disperse Violet 43; CI Disperse Blue 96; CI Fluorescent Brighteners 112, 135 and 163; CI Solvent Orange 2 and 45; CI Solvent Red 1, 3, 8, 23, 24, 25, 27 and 49; CI Pigment Green 10; CI Pigment Brown 2, etc. The light absorbing agent is usually blended in an amount of 10% by mass or less, preferably 5% by mass or less, based on the total solid content of the lithographic underlayer film material.

The rheology modifier mainly improves the fluidity of the resist underlayer film forming composition, particularly in the baking step, the film thickness uniformity of the resist underlayer film is improved or the resist underlayer film forming composition is added to the pore inside. The filling is added for the purpose. Specific examples include phthalic acid derived from dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, dihexyl phthalate, and butyl isoamyl phthalate. Adipic acid derivative, di-n-butyl adipate, diisobutyl adipate, diisooctyl adipate, octyl decyl adipate, di-n-butyl maleate, Malay An oleic acid derivative such as diethyl maleate or dinonyl maleate, a oleic acid derivative such as methyl oleate, butyl oleate or tetrahydrofurfuryl oleate; or n-butyl stearate; A stearic acid derivative such as glyceryl stearate. All solid layers of the underlayer film material relative to the lithography The body composition, such rheology modifiers are usually blended in a proportion of less than 30% by mass.

The adhesion aid is mainly added to improve the adhesion between the substrate or the resist and the underlayer film forming composition, and in particular, the resist is not peeled off during development. Specific examples thereof include chlorodecanes such as trimethylchlorodecane, dimethylvinylchlorodecane, methyldiphenylchlorodecane, and chloromethyldimethylchloromethane, and trimethylmethoxydecane. Alkoxy decane such as dimethyldiethoxy decane, methyl dimethoxy decane, dimethyl vinyl ethoxy decane, diphenyl dimethoxy decane, phenyl triethoxy decane a decane, vinyl such as hexamethyldioxane, N,N'-bis(trimethyldecyl)urea, dimethyltrimethyldecylamine, trimethyldecyl imidazole or the like a decane such as trichloromethane, γ-chloropropyltrimethoxydecane, γ-aminopropyltriethoxydecane, γ-glycidoxypropyltrimethoxydecane, benzotriazole or benzene Imidazole, oxazole, imidazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoene a heterocyclic compound such as azole, urazol, thiouracil, decyl imidazole or decylpyrimidine; or a urea such as 1,1-dimethylurea or 1,3-dimethylurea or a thiourea compound. These adhesion aids are usually less than 5% by mass, preferably less than 2% by mass, based on the total solid content of the lithographic underlayer film material.

In the underlayer film material for lithography of the present invention, a surfactant may be blended in order to further improve coating properties against surface unevenness so as not to cause pinholes or streaks. Examples of the surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, and polyoxyethylene oleyl ether. Vinyl octylphenol ether, poly Polyoxyethylene alkyl allyl ethers such as oxyethylene nonyl phenol ether, polyoxyethylene ‧ polyoxypropylene block copolymers, sorbitan monolaurate, sorbitan monopalmitate, Sorbitol fatty acid esters such as sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, sorbitan tristearate, polyoxyethylene Sorbitol monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan trioleate, polyoxyethylene sorbitol Nonionic surfactant such as polyoxyethylene sorbitan fatty acid ester such as sugar anhydride tristearate, Eftop EF301, EF303, EF352 (trade name, manufactured by TOHKEM PRODUCTS), Megafac F171, F173, R-30 (made by Dainippon Ink Co., Ltd., trade name), Fluorad FC430, FC431 (Sumitomo 3M (share), trade name), Asahiguard AG710, Surflon S-382, SC101, SC102, SC103, SC104, Fluorine-based surfactant such as SC105 and SC106 (Asahi Glass Co., Ltd., trade name), organic siloxane polymer KP3 41 (Shin-Etsu Chemical Industry Co., Ltd.) and so on. The blending amount of these surfactants is usually 2.0% by mass or less, preferably 1.0% by mass or less, based on the total solid content of the lithographic underlayer film material of the present invention. These surfactants may be added singly or in combination of two or more.

In the present invention, as a solvent for dissolving the above polymer, a crosslinking agent component, a crosslinking catalyst, or the like, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and methyl cellosolve acetate may be used. Ethyl cellosolve acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether Propylene glycol monoethyl Ether acetate, propylene glycol propyl ether acetate, toluene, xylene, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethyl 2-hydroxypropionate, 2-hydroxy-2-methylpropionic acid Ethyl ester, ethyl ethoxyacetate, ethyl hydroxyacetate, methyl 2-hydroxy-3-methylbutanoate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, 3- Ethyl ethoxypropionate, methyl 3-ethoxypropionate, methyl trimethylacetate, ethyl trimethylacetate, ethyl acetate, butyl acetate, ethyl lactate, butyl lactate and the like. These organic solvents may be used singly or in combination of two or more.

Further, a high boiling point solvent such as propylene glycol monobutyl ether or propylene glycol monobutyl ether acetate may be used in combination. Among these solvents, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate, and cyclohexanone are preferred for the improvement of the leveling property.

The resist used in the present invention is a photoresist or an electron line resist.

As the photoresist applied to the upper portion of the lower film of the lithographic resist for use in the present invention, either a negative type or a positive type may be used, and a novolac resin and 1,2-naphthoquinonediazide may be used. A positive-type photoresist composed of an acid ester, a chemically amplified photoresist composed of a binder and a photoacid generator having a base which is decomposed by an acid to increase the alkali dissolution rate, and an alkali-soluble binder and a caustic agent A chemically amplified photoresist comprising a low molecular compound and a photoacid generator which are decomposed by an acid to increase the alkali dissolution rate of the photoresist, and a binder having a base which is decomposed by an acid to increase the alkali dissolution rate and A chemically amplified photoresist composed of a low molecular compound and a photoacid generator which have an alkali dissolution rate of a photoresist which is decomposed by an acid, and a photoresist having a Si atom in the skeleton, and the like, for example, Rohm & Haas company's trade name APEX-E.

In addition, examples of the electron ray resist applied to the upper portion of the underlayer film for a lithography resist in the present invention include a resin containing a Si-Si bond in the main chain and an aromatic ring at the terminal. A composition composed of an acid generator which generates an acid by irradiation of an electron beam, or a poly(p-hydroxystyrene) substituted with a hydroxyl group via an organic group containing an N-carboxyamine and an acid generated by irradiation of an electron beam a composition composed of the agent and the like. In the latter electron-resistance composition, an acid generated from an acid generator by electron beam irradiation reacts with an N-carboxyamino group of a polymer side chain, and a polymer side chain is decomposed into a hydroxyl group to exhibit alkali solubility. Dissolved in the alkali imaging solution to form a resist pattern. Examples of the acid generator which generates an acid by irradiation of an electron beam include 1,1-bis[p-chlorophenyl]-2,2,2-trichloroethane and 1,1-bis[p-methoxybenzene. 2,2,2-trichloroethane, 1,1-bis[p-chlorophenyl]-2,2-dichloroethane, 2-chloro-6-(trichloromethyl)pyridine, etc. a sulfonate such as a halogenated organic compound, a triphenylsulfonium salt or a diphenyliodonium salt or the like, a nitrobenzyl tosylate or a dinitrobenzyl tosylate.

As a developing solution having a resist of a resist underlayer film formed using the underlayer film material for a lithography resist of the present invention, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium citrate or sodium metasilicate may be used. An inorganic base such as ammonia, a first-grade amine such as ethylamine or n-propylamine, a second-grade amine such as diethylamine or di-n-butylamine, or a triethylamine or methyldiethylamine. a tertiary amine such as a tertiary amine, dimethylethanolamine or triethanolamine, a fourth ammonium salt such as tetramethylammonium hydroxide, tetraethylammonium hydroxide or choline, or a cyclic amine such as pyrrole or piperidine. An aqueous solution of the base. Further, an appropriate amount of an alcohol such as isopropyl alcohol or a surfactant such as a nonionic surfactant may be added to the aqueous solution of the above-mentioned alkali. Among these, a preferred developing solution is a fourth-order ammonium salt, more preferably tetramethylammonium hydroxide and choline.

Next, a resist pattern forming method of the present invention will be described, which is a substrate (for example, a tantalum/cerium oxide coating, a glass substrate, an ITO substrate, or the like) used for the manufacture of a precision integrated circuit component. A suitable coating method such as a spin coater or a coater is applied to form a composition of a resist underlayer film, followed by baking to be cured to prepare a coating type underlayer film. Here, the film thickness of the resist underlayer film is preferably from 0.01 to 3.0 μm. Further, the conditions for baking after coating are carried out at 80 to 350 ° C for 0.5 to 120 minutes. Then, directly or on the lower layer film of the resist, a coating film material of 1 to several layers is formed on the coating type underlayer film, and then a resist is applied, and light or electron lines are applied through a specified mask. Irradiation, by developing, rinsing, and drying, a good resist pattern can be obtained. It can also be heated by irradiation with light or electron rays (PEB: Post Exposure Bake) as needed. The resist underlayer film is then removed by dry etching to remove portions of the resist that have been removed by the previous steps, and the desired pattern can be formed on the substrate.

The exposure light of the above photoresist is a chemical line such as near ultraviolet light, far ultraviolet light or extreme ultraviolet light (for example, EUV, wavelength 13.5 nm), for example, 248 nm (KrF laser light), 193 nm (ArF laser light), 157 nm (F ₂ Ray). Light of a wavelength such as light). In the light irradiation, as long as it can produce an acid from a photoacid generator, it can be used without particular limitation, and the exposure amount is 1 to 2000 mJ/cm ² , or 10 to 1500 mJ/cm ² , or 50 to 1000 mJ/cm. ² .

Moreover, the electron beam irradiation of the electron line resist can be irradiated by, for example, electron beam The device is illuminated.

In the present invention, the semiconductor device can be manufactured by the steps of forming a resist underlayer film on a semiconductor substrate by forming a composition of a resist underlayer film, and forming a resist film thereon by using light. Or the step of forming a resist pattern by electron beam irradiation and development, the step of etching the resist underlayer film according to the resist pattern, and the step of processing the semiconductor substrate by the patterned resist underlayer film.

In the future, when the resist pattern is miniaturized, there is a problem of resolution or a problem that the resist pattern collapses after development, and it is desirable to form a thin film of the resist. Therefore, it is difficult to obtain a sufficient resist pattern thickness in the substrate processing, and it becomes a resist underlayer film which is formed not only in the resist pattern but also between the resist and the processed semiconductor substrate, and also needs to be maintained as a substrate. The function of the masking function. As a resist underlayer film for such a process, unlike the conventional high etch rate resist underlayer film, a lithographic resist underlayer film having a selection ratio close to the dry etching rate of the resist is required, which is smaller than the resist. The etch rate of the selection ratio of the dry etching rate is a resist film underlayer film or a resist film underlayer film having a selection ratio of a dry etching rate smaller than that of the semiconductor substrate. Moreover, such a resist underlayer film can also provide an antireflection ability and can function as a conventional antireflection film.

On the other hand, in order to obtain a fine resist pattern, a process in which the pattern of the resist and the lower film of the resist are thinner than that of the resist under the resist is used in the dry etching of the underlayer film. As a resist underlayer film for such a process, unlike the conventional high etch rate antireflection film, a resist underlayer film having a selection ratio close to the dry etching rate of the resist is required. Again, for such a resist The underlayer film can also impart anti-reflection capability and can function as a conventional anti-reflection film.

In the present invention, after the film of the resist underlayer of the present invention is formed on the substrate, one to several layers of the film material can be formed directly on the resist underlayer film or as needed. After the upper layer, a resist is applied. Thereby, the pattern width of the resist is narrowed, and even when the resist is thinned to prevent the pattern from collapsing, the substrate can be processed by selecting an appropriate etching gas.

That is, the semiconductor device can be manufactured by forming a composition by a resist underlayer film, forming a resist underlayer film on the semiconductor substrate, and forming a coating film material containing a bismuth component or the like thereon. a hard mask or a hard mask formed by vapor deposition (for example, ruthenium oxynitride), and a step of forming a resist film thereon, which is formed by light or electron beam irradiation and development to form a resist pattern a step of etching the hard mask by a halogen-based gas according to a resist pattern, and etching the resist underlayer film by an oxygen-based gas or a hydrogen-based gas through a patterned hard mask, and The step of processing the semiconductor substrate with a halogen-based gas by the patterned resist underlayer film.

The lithographic underlayer film forming composition of the present invention, when considering the effect as an anti-reflection film, since the light absorbing portion is incorporated into the skeleton, there is no diffusing agent to the photoresist during heat drying, and The light absorbing portion has sufficient light absorbing properties, and the effect of antireflection light is high.

The lithographic underlayer film forming composition of the present invention has high heat stability, prevents contamination of the upper layer film by the decomposition product at the time of firing, and has a margin in the temperature limit of the firing step.

Furthermore, the lithographic underlayer film material of the present invention is used as a film having the following functions depending on the process conditions: a function of preventing reflection of light, and further preventing interaction between the substrate and the photoresist, or The adverse effect of the material used for the photoresist or the substance generated when the photoresist is exposed on the substrate is prevented.

Example <Synthesis Example 1>

1,1,2,2-tetrakis(4-hydroxyphenyl)ethane (product name: TEP-DF, manufactured by Asahi Organic Materials Co., Ltd.) 8.65 g, 1-indole formaldehyde (Maruzen Chemical Industry Co., Ltd.) Into 5.00 g of methanesulfonic acid (0.21 g), 20.79 g of propylene glycol monomethyl ether was added, and the mixture was stirred under reflux for 23 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was diluted with 35 g of tetrahydrofuran, and the diluted solution was reprecipitated from a mixed solvent of methanol/water (50% by mass/50% by mass). The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 9.4 g of a novolak resin (polymer containing the formula (8-1)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 3,600.

<Synthesis Example 2>

1,1,2,2-tetrakis(4-hydroxyphenyl)ethane (product name: TEP-DF, manufactured by Asahi Organic Materials Co., Ltd.) 6.06 g, 1-indole formaldehyde (Maruzen Chemical Industry Co., Ltd.) 20.0 g of propylene glycol monomethyl ether was added to 7.00 g of methanesulfonic acid and 0.29 g of methanesulfonic acid, and the mixture was stirred under reflux for 23 hours under a nitrogen atmosphere. After the reaction was completed, it was diluted with 20 g of tetrahydrofuran to make a dilution from methanol/water (80% by mass/20). Re-precipitated in a mixed solvent of % by mass. The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 9.1 g of a novolak resin (a polymer containing the formula (8-20)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 4,800.

<Synthesis Example 3>

1,1,2,2-tetrakis(4-hydroxyphenyl)ethane (product name: TEP-DF, manufactured by Asahi Organic Materials Co., Ltd.) 3.89 g, 1-indole formaldehyde (Maruzen Chemical Industry Co., Ltd.) 19.00 g of the product and 0.38 g of methanesulfonic acid were added to 19.90 g of propylene glycol monomethyl ether, and the mixture was stirred under reflux for 23 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was diluted with 20 g of tetrahydrofuran, and the diluted solution was reprecipitated from a mixed solvent of methanol/water (80% by mass/20% by mass). The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 11.2 g of a novolak resin (polymer containing the formula (8-22)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 5,700.

<Synthesis Example 4>

α,α,α',α'-tetrakis(4-hydroxyphenyl)-p-xylene (product name: TEP-TPA, manufactured by Asahi Organic Materials Co., Ltd.) 10.30g, 1-indole formaldehyde (Maruzen Chemical Co., Ltd.) Industrial Co., Ltd.) 5.00 g and 0.21 g of methanesulfonic acid were added 23.27 g of propylene glycol monomethyl ether, and the mixture was stirred under reflux for 23 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was diluted with 39 g of tetrahydrofuran, and the diluted solution was reprecipitated from a mixed solvent of methanol/water (50% by mass/50% by mass). The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 10.0 g of a novolak resin (containing formula (8-5) Polymer). The weight average molecular weight measured by GPC in terms of standard polystyrene was 4,900.

<Synthesis Example 5>

Αα,α,α',α'-tetrakis(4-hydroxyphenyl)-p-xylene (product name: TEP-TPA, manufactured by Asahi Organic Materials Co., Ltd.) 7.21g, 1-indole formaldehyde (Maruzen Chemical Co., Ltd.) To 7.00 g of methylenesulfonic acid and 0.29 g of methanesulfonic acid, 23.27 g of propylene glycol monomethyl ether was added, and the mixture was stirred under reflux for 23 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was diluted with 22 g of tetrahydrofuran, and the diluted solution was reprecipitated from a mixed solvent of methanol/water (80% by mass/20% by mass). The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 10.2 g of a novolak resin (polymer containing the formula (8-26)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 7,900.

<Synthesis Example 6>

α,α,α',α'-tetrakis(4-hydroxyphenyl)-p-xylene (product name: TEP-TPA, manufactured by Asahi Organic Materials Co., Ltd.) 4.64 g, 1-indole formaldehyde (Maruzen Chemical Co., Ltd.) Industrial Co., Ltd.), 9.00 g, and 0.38 g of methanesulfonic acid, 21.02 g of propylene glycol monomethyl ether was added, and the mixture was stirred under reflux for 23 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was diluted with 21 g of tetrahydrofuran, and the diluted solution was reprecipitated from a mixed solvent of methanol/water (80% by mass/20% by mass). The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 10.9 g of a novolak resin (containing a polymer of the formula (8-28)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 7,400.

<Synthesis Example 7>

1,1,2,2-tetrakis(3-methyl-4-hydroxyphenyl)ethane (product name: TEOC-DF, manufactured by Asahi Organic Materials Co., Ltd.) 9.87 g, 1-indole formaldehyde (Maruzen 5.00 g of a chemical industry (manufactured by KK) and 22.1 g of methanesulfonic acid were added, and 22.62 g of propylene glycol monomethyl ether was added, and the mixture was stirred under reflux for 23 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was diluted with 38 g of tetrahydrofuran, and the diluted solution was reprecipitated from a mixed solvent of methanol/water (50% by mass/50% by mass). The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 6.9 g of a novolak resin (polymer containing the formula (8-2)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 1,700.

<Synthesis Example 8>

1,1,2,2-tetrakis(3-methyl-4-hydroxyphenyl)ethane (product name: TEOC-DF, manufactured by Asahi Organic Materials Co., Ltd.) 4.69 g, 1-indole formaldehyde (Maruzen To 9.50 g of methanesulfonic acid (manufactured by Chemical Industry Co., Ltd.), 21.88 g of propylene glycol monomethyl ether was added, and the mixture was stirred under reflux for 23 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was diluted with 36 g of tetrahydrofuran, and the diluted solution was reprecipitated from a mixed solvent of methanol/water (70% by mass/30% by mass). The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 11.5 g of a novolak resin (polymer containing the formula (8-25)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 2000.

<Synthesis Example 9>

1,1,2,2-tetrakis(4-hydroxyphenyl)ethane (product name: TEP-DF, manufactured by Asahi Organic Materials Co., Ltd.) 4.35 g, 9-furaldehyde 9.00 g, methanesulfonic acid 0.42 In g, 20.65 g of propylene glycol monomethyl ether was added, and the mixture was stirred under reflux for 24 hours under a nitrogen atmosphere. After the completion of the reaction, the solution was reprecipitated from a mixed solvent of methanol/water (60% by mass/40% by mass). The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 9.9 g of a novolak resin (polymer containing the formula (8-29)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 1,300.

<Synthesis Example 10>

To 9.28 g of tris(4-hydroxyphenyl)methane, 21.28 g of 1-indolecarboxaldehyde (manufactured by Maruzen Chemical Co., Ltd.), and 0.89 g of methanesulfonic acid, 57.89 g of propylene glycol monomethyl ether was added, and refluxed under a nitrogen atmosphere. Stir for 25 hours. After completion of the reaction, it was diluted with 63 g of tetrahydrofuran to reprecipitate the diluted solution from methanol. The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 20.1 g of a novolak resin (polymer containing the formula (8-18)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 3,200.

<Synthesis Example 11>

To 5.90 g of tris(4-hydroxyphenyl)ethane, 4.50 g of 1-nonanaldehyde (manufactured by Maruzen Chemical Co., Ltd.), and 0.19 g of methanesulfonic acid, 16.01 g of propylene glycol monomethyl ether was added under a nitrogen atmosphere. Stir under reflux for 14 hours. After completion of the reaction, the mixture was diluted with 9 g of tetrahydrofuran to reprecipitate the diluted solution from methanol/water (80% by mass/20% by mass). Filter and wash the resulting precipitate and decompress at 60 ° C It was dried to obtain 4.9 g of a novolak resin (a polymer containing the formula (8-19)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 2,300.

<Synthesis Example 12>

8.5 g of 1,5-dihydroxynaphthalene 5.56 g and 1-indolecarboxaldehyde (manufactured by Maruzen Chemical Industry Co., Ltd.) were added, and the mixture was stirred under reflux for 24 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was diluted with 35 g of tetrahydrofuran to reprecipitate the diluted solution from methanol. The obtained precipitate was filtered and washed, and dried under reduced pressure at 60 ° C to obtain 9.3 g of a novolak resin (polymer containing the formula (12-1)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 3,100.

<Synthesis Example 13>

2,2-bis[4,4-bis(4-hydroxyphenyl)cyclohexyl]propane (product name: TEP-BOCP, manufactured by Asahi Organic Materials Co., Ltd.) 8.14 g, 1-indole formaldehyde (Maruzen Chemical Co., Ltd.) Industrial Co., Ltd., 6.50 g, and 0.27 g of methanesulfonic acid, 22.37 g of propylene glycol monomethyl ether was added, and the mixture was stirred under reflux for 23 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was diluted with 37 g of tetrahydrofuran, and the diluted solution was reprecipitated from a mixed solvent of methanol/water (50% by mass/50% by mass). Filtered and washed The precipitate was dried under reduced pressure at 60 ° C to obtain 10.4 g of a novolac resin (a polymer containing the formula (12-2)). The weight average molecular weight measured by GPC in terms of standard polystyrene was 3,500.

<Example 1>

After dissolving 3.0 g of the polymer obtained in Synthesis Example 1 in 19.2 g of propylene glycol monomethyl ether and 8.2 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Example 2>

After dissolving 3.3 g of the polymer obtained in Synthesis Example 2 in 20.8 g of propylene glycol monomethyl ether and 8.9 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Example 3>

After dissolving 3.2 g of the polymer obtained in Synthesis Example 3 in 20.1 g of propylene glycol monomethyl ether and 8.6 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Example 4>

After dissolving 3.5 g of the polymer obtained in Synthesis Example 4 in 22.3 g of propylene glycol monomethyl ether and 9.5 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Example 5>

After dissolving 3.2 g of the polymer obtained in Synthesis Example 5 in 20.2 g of propylene glycol monomethyl ether and 8.7 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Example 6>

After dissolving 3.2 g of the polymer obtained in Synthesis Example 6 in 20.0 g of propylene glycol monomethyl ether and 8.6 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Example 7>

After dissolving 2.0 g of the polymer obtained in Synthesis Example 7 in 12.6 g of propylene glycol monomethyl ether and 5.4 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Example 8>

After dissolving 3.0 g of the polymer obtained in Synthesis Example 8 in 18.9 g of propylene glycol monomethyl ether and 8.1 g of cyclohexanone, lithography for multilayer film was prepared. The solution of the underlayer film of the processant forms a composition.

<Example 9>

After dissolving 3.0 g of the polymer obtained in Synthesis Example 9 in 18.9 g of propylene glycol monomethyl ether and 8.1 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Example 10>

After dissolving 3.0 g of the polymer obtained in Synthesis Example 10 in 18.9 g of propylene glycol monomethyl ether and 8.1 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Example 11>

After dissolving 1.4 g of the polymer obtained in Synthesis Example 11 in 13.0 g of propylene glycol monomethyl ether and 5.6 g of propylene glycol monomethyl ether acetate, the composition of the underlayer film for the lithography process of the multilayer film was prepared. a solution of matter.

<Comparative Example 1>

After dissolving 2.0 g of the polymer obtained in Synthesis Example 12 in 12.6 g of propylene glycol monomethyl ether and 5.4 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

<Comparative Example 2>

2.0 g of the polymer obtained in Synthesis Example 13 was dissolved in propylene glycol monomethyl After 11.6 g of a group ether and 5.4 g of cyclohexanone, a solution for forming a composition of a resist underlayer film for a lithography process of a multilayer film was prepared.

(Measurement of bending resistance of pattern)

Each of the solutions of the respective underlayer film forming compositions prepared in Examples 1 to 11, Comparative Example 1, and Comparative Example 2 was applied onto a tantalum wafer with a ruthenium oxide film by a spin coater. The film was baked at 400 ° C for 2 minutes on a hot plate to form a resist underlayer film (film thickness: 200 nm). A composition of the composition was formed by coating a hard mask on the underlayer film, and firing at 240 ° C for 1 minute to form a hard mask layer (film thickness: 45 nm). A resist solution was applied thereon, and baked at 100 ° C for 1 minute to form a resist layer (film thickness: 120 nm). Using a mask, the film was exposed at a wavelength of 193 nm, and after exposure, PEB was heated (105 ° C for 1 minute), and developed to obtain a resist pattern. Then, dry etching is performed with a fluorine-based gas (component is CF ₄ ), and the resist pattern is transferred to the hard mask. Then, dry etching is performed with an oxygen-based gas (component is O ₂ /CO ₂ ), and the resist pattern is transferred to the underlayer film of the resist. Then, dry etching is performed using a fluorine-based gas (component: C ₄ F ₆ /C ₄ F ₈ /O ₂ /Ar) to remove the cerium oxide film on the germanium wafer. Then, dry etching is performed with an oxygen-based gas (component: O ₂ /N ₂ ) to remove a resist underlayer film formed on the cerium oxide film to form a composition. The respective pattern shapes at the respective steps were observed with an electron microscope. As the width of the pattern is narrowed, it becomes easy to cause an irregular pattern called wiggling, and the formation of the pattern is performed by observing the composition of the resist underlayer film of the above embodiment by an electron microscope. The width of the pattern of the wiggling. Since the pattern is bent and it is impossible to complete the substrate processing based on the faithful pattern, it is necessary to perform the substrate processing by the pattern width (the limit processing line width) immediately before the pattern is bent. The width of the pattern at which the pattern begins to bend is the more the value of the substrate is processed. For the measurement of the resolution, a length-measuring scanning electron microscope (manufactured by Hitachi, Ltd.) was used. The underlayer film of the resist remaining on the cerium oxide film was removed to form a constituent film, and the processing line width of the yttrium oxide film which had been transferred in stages of the resist pattern was measured. Table 1 shows the processing line width at which the pattern formed on the yttrium oxide film starts to be bent at this time.

Example 1

From the above results, it was confirmed that compared with Comparative Example 1 and Comparative Example 2, The pattern formed by the resist underlayer film forming compositions of Examples 1 to 10 on the yttrium oxide film was bent to have a narrower processing line width, and a finer substrate processing was achieved. Namely, it was confirmed that the resist underlayer film forming compositions of Examples 1 to 10 showed an effect of suppressing the wiggling of the pattern.

(solubility test)

The solutions of the respective underlayer film forming compositions prepared in Examples 1 to 11, Comparative Example 1 and Comparative Example 2 were dropped to a general resist solvent of propylene glycol monomethyl ether (PGME), propylene glycol monomethyl group. In the ether acetate (PGMEA) or cyclohexanone (CYH), it was observed whether or not a precipitate of a polymer (novolac resin component) in the underlayer film forming composition was precipitated. When the precipitation was not observed, the solubility of the novolak resin was regarded as "good", and when the precipitation was observed, the solubility of the novolak resin was regarded as "poor". The results of the solubility test of this novolak resin solution are shown in Table 2.

From the above results, it was confirmed that the resist underlayer film forming compositions of Examples 1 to 11 were more soluble in the resist solvent than Comparative Example 1.

(flattening test)

The solutions of the respective underlayer films of the respective resists prepared in Examples 1 to 11, Comparative Example 1, and Comparative Example 2 were formed into a composition by a spin coater to have a film thickness of 90 nm. The SiO ₂ wafer substrate having a gap (pattern width: 75 nm, pitch width: 340 nm, pattern height: 80 nm) was baked on a hot plate at 400 ° C for 2 minutes to form an underlayer film. Using a scanning electron microscope (SEM), a wafer having a line and a gap of SiO ₂ coated with the underlayer film forming composition for lithography obtained in Examples 1 to 11, Comparative Example 1, and Comparative Example 2 was observed. The cross-sectional shape of the substrate was evaluated for the planarization of the underlying film for the line and gap patterns. The lower film was regarded as "good" in the case where the line and the gap pattern were applied without unevenness, and the case where the slight unevenness was observed was regarded as "slightly defective", and the case where the unevenness was observed was regarded as "poor". The results of this flattening test are shown in Table 3.

From the above results, it was confirmed that Example 1 was compared with Comparative Example 1. The resist film lower layer film forming composition of 11 is more excellent in planarization property.

(burial test)

The solution of each of the resist underlayer films prepared in Examples 1 to 11, Comparative Example 1, and Comparative Example 2 was formed into a composition by a spin coater, and was applied to have a hole pattern so as to have a film thickness of 200 nm. The SiO ₂ -coated wafer substrate of the type (pore diameter: 120 nm, pitch width: 240 nm, depth: 400 nm) was fired on a hot plate at 400 ° C for 2 minutes to form an underlayer film. Using a scanning electron microscope (SEM), a wafer having a hole pattern of SiO ₂ coated with the underlayer film forming composition obtained in Examples 1 to 10, Comparative Example 1, and Comparative Example 2 was observed. The cross-sectional shape of the substrate was evaluated for the embedding property of the underlayer film under the hole pattern. The case where the underlayer film is buried in a hole pattern without holes is regarded as "good", and the case where a hole is formed in the hole pattern is regarded as "poor". The results of this embedding test are shown in Table 4.

From the above results, it was confirmed that the resist underlayer film forming compositions of Examples 1 to 11 were more excellent in embedding property than Comparative Example 1.

Industrial use possibility

Therefore, the resist underlayer film material used in the lithography process of the multilayer film of the present invention can provide a resist underlayer film which, unlike the conventional high etch rate anti-reflection film, can have a photoresist or a ratio close to that of the photoresist. The selection ratio of the small dry etching rate of the photoresist is smaller than the selection ratio of the dry etching rate of the semiconductor substrate, and also has an effect as an antireflection film. Moreover, by baking the film at 400 ° C, compared with the dry etching rate ratio of the phenol novolak resin of the conventional product, it is understood that it has a function as a hard mask, so that it is displayed at 400 ° C or higher. Heat resistance.

The underlayer film material of the present invention was vapor-deposited on the upper layer, and it was found that heat resistance capable of forming a hard mask was obtained.

Claims (12)

A resist underlayer film forming composition comprising a structure having at least three phenol groups bonded to a third-order carbon atom, or having a phenol group bonded to a methyl group A phenol novolak resin obtained by reacting a compound having a structure of a quaternary carbon atom with an aromatic aldehyde or an aromatic ketone in the presence of an acidic catalyst. A resist underlayer film forming composition according to claim 1, wherein the phenol novolac resin comprises a unit structure of the following formula (1), a unit structure of the formula (2), a unit structure of the formula (3), and a formula (4). Unit construction or a combination of their unit constructions: In the formula (1), the formula (2), the formula (3), and the formula (4), the A group has an organic group having at least three phenol groups and the phenol group is bonded to the third-order carbon atom, and B ¹ , B ² , B ³ and B ⁴ each represent the formula (5): (In the formula (5), C ¹ represents an aryl or heterocyclic group having 6 to 40 carbon atoms which may be substituted by a halogen group, a nitro group, an amine group or a hydroxyl group, and C ² represents a hydrogen atom or may be a halogen group or a nitro group. , an amino group or a hydroxy group substituted with an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 40 carbon atoms or a heterocyclic group, and C ¹ and C ² may also form a ring together with the carbon atom to which they are bonded) ]. The underlayer film forming composition of claim 2, wherein the above A is represented by the formula (6), (In the formula (6), T-based single bond, an alkylene group having a carbon number of 1 to 10, carbon atoms or an arylene group having 6 to 40, X ¹ and X ² are each a hydrogen atom or a methyl-based, R ¹ to R ^{4 is} each a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ⁵ to R ⁸ are each an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms, and n ¹ to n ⁴ each represent 0 to 3 An integer of each phenol group is suitably bonded to the above B ¹ , B ² , B ³ and B ⁴ ). The underlayer film forming composition of claim 2, wherein the above A is represented by the formula (7), (In the formula (7), each of R ⁹ to R ¹¹ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and each of R ¹² to R ¹⁴ is an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms. X ³ is a hydrogen atom or a methyl group, and n5 to n7 each represent an integer of 0 to 3, and each phenol group is appropriately bonded to the above B ¹ , B ² , B ³ and B ⁴ ). The resist underlayer film forming composition according to any one of claims 2 to 4, wherein the above C ¹ is a mercapto group or a mercapto group. The resist underlayer film forming composition according to any one of claims 1 to 4, which further contains a crosslinking agent. The resist underlayer film forming composition according to any one of claims 1 to 5, which further contains an acid and/or an acid generator. A resist underlayer film obtained by applying a resist underlayer film forming composition according to any one of claims 1 to 7 onto a semiconductor substrate and baking it. A method for forming a resist pattern for use in the manufacture of a semiconductor, comprising applying a resist underlayer film forming composition according to any one of claims 1 to 7 to a semiconductor substrate, and firing to form an underlayer film The steps. A method of manufacturing a semiconductor device, comprising: forming a composition film on a semiconductor substrate by forming a composition of a resist underlayer film according to any one of claims 1 to 7, forming a resist film thereon; a step of forming a resist pattern by irradiation and development of light or electron lines, etching the underlayer film according to a resist pattern, and processing the semiconductor substrate by patterning the underlayer film step. A method of manufacturing a semiconductor device, comprising: forming a lower film by forming a composition of a resist underlayer film according to any one of claims 1 to 7 on a semiconductor substrate, and forming a hard mask thereon a step of forming a resist film thereon by a step of forming a resist pattern by irradiation and development of light or electron lines, and etching the hard mask by a resist pattern, by means of a step of etching a hard mask by a resist pattern The step of patterning the hard mask to etch the underlying film and the step of processing the semiconductor substrate by patterning the underlying film. The manufacturing method of claim 11, wherein the hard mask is formed by evaporation of an inorganic material.